Ischemic stroke is associated with a systemic increase of blood mononuclear cells expressing interleukin-8 mRNA.
OBJECTIVE
Ischemic brain injury secondary to an arterial occlusion is characterized by acute local inflammation. Blood polymorphonuclear leukocytes (PMNL), primarily neutrophils, adhere to endothelial cells and rapidly invade the injured brain after the arterial occlusion. This neutrophilic invasion might correlate with the production of certain chemoattractants by blood mononuclear cells (MNC). We evaluated mRNA expression of the CXC chemokine interleukin (IL)-8, and the CC chemokines monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta in blood MNC from patients with ischemic stroke.


METHODS
Peripheral blood was obtained at 8 AM on days 1 to 7 (mean, day 3) after onset of symptoms. In situ hybridization with radiolabeled synthetic oligonucleotide probes for the chemokines was adopted to measure chemokine mRNA expression in MNC. An enzyme-linked immunosorbent assay for IL-8 was used to measure IL-8 levels in plasma.


RESULTS
Most patients with ischemic stroke had high numbers of IL-8 mRNA expressing blood MNC, regardless of the time interval between onset of clinical symptoms and examination. There was a marked difference between patients with ischemic stroke and healthy subjects (median, 6228 versus 885 positive cells per 10(5) MNC; P<.0001). IL-8 levels in plasma correlated positively to IL-8 mRNA expression in examined patients (n=7) with ischemic stroke (r=.78, P<.05). In contrast, mRNA expression for the CC chemokines showed no significant difference between patients with ischemic stroke and healthy control subjects.


CONCLUSIONS
This study demonstrated a systemic increase of IL-8 mRNA expressing MNC and IL-8 levels in plasma from patients with ischemic stroke, suggesting that IL-8 could be involved in recruiting blood PMNL to the sites of cerebral ischemia.
Kostulas
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N
Division of Neurology, Karolinska Institute, Huddinge University Hospital, Stockholm, Sweden. Nikolakis@hotmail.com
Kivisäkk
P
P
Huang
Y
Y
Matusevicius
D
D
Kostulas
V
V
Link
H
H
D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000097:blood / Q000276:immunology*; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000097:blood; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D019402:Macrophage Inflammatory Proteins / Q000096:biosynthesis / Q000097:blood; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000096:biosynthesis; D012016:Reference Values; D012044:Regression Analysis; D014158:Transcription, Genetic
D018932:Chemokine CCL2; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D016209:Interleukin-8; D019402:Macrophage Inflammatory Proteins; D012333:RNA, Messenger